After a week of grief and frustration, the family of Indian student Anuj Bidve has hit out at the British authorities, accusing police and officials of dragging their feet and failing to help them in their hour of need.

The 23-year-old was shot in the head in the early hours of Boxing Day as he walked through Salford with a group of eight Indian friends, fellow students from Lancaster University. His family say the authorities need to do more to restore their faith in Britain and to prove to them that the UK is not a racist country.

Police have offered a £50,000 reward in an attempt to catch the killers. They have made a number of arrests and categorised the killing as a "hate crime", but Bidve's family in the Indian city of Pune are becoming increasingly angry about the handling of the case.

They have accused the police of failing to contact them to inform them of their son's death – they only found out when his friends started to contact them through Facebook – and of neglecting the case because it was the festive season.

The delay in getting Bidve's body home has infuriated family members, who say the British authorities were more concerned about Christmas and the new year festivities than in helping the family observe their traditions.

"It is unacceptable to us," said Rakesh Sonawane, Bidve's brother-in-law. "They say the investigation is still pending, the charge sheet has not been filed and a second postmortem is still pending. The holidays are taking their toll. If there were more people working, we would not have to wait so long.

It is a very sensitive issue for any Indian. If someone dies, we have to perform all the rites. We burn the body on the day of death and for the next 13 days we have to do several other things, otherwise the soul might not rest in peace."

He said that he and Bidve's father, Subhash, were ready to fly to Britain to bring the body home, but despite help from the Indian authorities there had been no progress in getting it released.

Early this morning Manchester police announced that a senior officer, accompanied by a family liaison officer, are to fly to India today to meet the family.

Sonawane said the family was reluctant to come up with charges of racism against Britain, but they could not understand why they were being kept in the dark. "It is extremely disappointing the way we have been treated. We still don't know what course of action was taken by the British police when they were informed of the attack. We don't know what hospital he was taken to, what treatment he received or whether he was taken there in time. We are told it took half an hour and that that is not normal for the UK. If there was a delay in taking him, why did that happen?"

He said the family were upset about the way they had been treated and that it had affected their view of Britain. "I really want that the UK authorities should help us in changing our perceptions," he said."We still have a lot of faith in the UK authorities and the police, but they have to help us more. They have to help us to believe again that Britain is not a racist place."

He said the family had been concerned about whether Britain was a safe place for an Indian to go before sending Bidve to college. "All my friends who have been to the UK have had some sort of bad experience there," he said. However, he said the young student was excited about the opportunity to study in Britain.

Three teenagers – one 16-year-old and two 17-year-olds – arrested in connection with the killing were granted bail on Friday. Another, aged 19, was released on bail last night and a 20-year-old remains in custody. The murder weapon has not been found.

Police have apologised to the family for the initial handling of the case, and in particular about the fact that they found out about the killing on Facebook. "That is not the way anyone should have to find out something so devastating and we completely understand how upset the family are," said Dawn Copley, the Greater Manchester Police assistant chief constable. She said police had attempted to track down the family, but were beaten by the social networking site. "Unfortunately, as the officer was attempting to contact the family through the right channels, a post was put on Facebook. We have no control over when and what people post, but no one should hear such tragic news in this way."

The student was shot in the head at point-blank range as he walked with friends near their hotel in the inner-city Ordsall district of Salford, in the early hours of 26 December.

Police say the gunman, a white man in his twenties who was wearing a grey top, walked across the road and spoke to Bidve before taking out a gun and shooting him in the side of the head. Police say the killing – which they described as "extremely unusual and savage" – may have been racially motivated.

British police plan to send officers to India to liaise with family members.